Hartebeesthoek (Hh) Station Report - TOG Meeting - November 2007 Session I - March 2007: This was our busiest session ever with a total of 21 experiments, of which 13 were user experiments, comprising some 81% of the 112 hours (31 hours C-band 3 hours K-band, 19 hours L-band and 59 hours Methanol) of recording time, and some 89% of the 14145 Gbytes of recorded Mark5A data. The average filling factor of the disk-packs was about 93% with all experiments destined for the JIVE correlator in this session. Only 3 minutes was lost during the entire session due to a local control system glitch, though significant RFI plagued the L-band part of the session. Session II - June 2007: A total of 12 experiments were recorded during this session, of which 8 were user experiments, comprising some 91% of the 100 hours ( 42 hours L-band and 58 hours Methanol) of recording time, and some 86% of the 4227 Gbytes of recorded Mark5A data. The average filling factor of the disk-packs was 88% with all experiments destined for JIVE. In total 11 hours (ie. 11%) of data was lost during the session, 1 hour due to a failure of the secondary subreflector control hardware and 10 hours due to an operator failing to turn up for a shift. Again significant RFI was experienced throughout the L-band part of the session. Session III - October/November 2007: Only 6 experiments were recorded during this session, of which 3 were user experiments, comprising some 70% of the 44 hours ( 5 hours L-band, 28 hours Methanol and 11 hours C-band) of recording time, and some 78% of the 6049 Gbytes of recorded Mark5A data. The average filling factor of the disk-packs was 82% with all data destined for JIVE, though one experiment will be sent on to the Swinburne software correlator after copying. About 50 minutes (ie. < 2%) of data was lost during the session, due to extensive failure of the local RF distribution hardware following a major leak in an equipment room during a cloud burst just prior to the EM067 experiment. Unfortunately this comprised a 42% loss of this experiment's data. Significant RFI was experienced throughout the L-band part of the session. Mark5A Recorder: This recorder has recently been upgraded to a new dual-processor motherboard with 4GB RAM plus two Gigabit ethernet interfaces suitable for e-VLBI. We have also procured all the components necessary for the conversion of this recorder into a Mark5B, but this upgrade has not been installed yet. The recorder continues to perform extremely reliably except at 1Gbps where many scan_checks indicate some byte dropping. Mark 4 Terminal: The zero level of the "IF2" detector in the IF distributor module has been re-adjusted to make it function correctly again. Components to enable the conversion of the Mark4 formatter into a VSI sampler suitable for use with a Mark5B recorder have been purchased but not yet installed, pending the conversion of the Mark 5 recorder itself. Frequency Standards: HartRAO continues to operate on our new EFOS-C maser (EFOS-28) which has performed flawlessly since its installation almost three years ago. Our old EFOS-A maser (EFOS-6) is currently non-functional, but hopefully repairable by replacement of the internal vacion pump. Telescope Surface: There has been no further progress on this issue since the last TOG meeting, holographic mapping of the remaining surface errors is still in process. Receivers: Since the last TOG meeting, a new dual polarisation ambient 22GHz receiver has been installed and is undergoing commissioning and calibration. We hope to upgrade this receiver to cryogenic amplifiers in the near future, as it seems that the surface accuracy is good enough for viable operation at this frequency. Other Hardware/Software: Field System: FS9.9.2 running on FS Linux 6 (Debian "sarge") kernel 2.4.27-3 Mark5A version: 2005y147d17h also running on Debian "sarge" kernel 2.4.27-3 Computer (and hence FS) control of the secondary reflector position to enable fast switching between all the available receivers is not yet operational pending installation of new limit switches plus further software optimisation. A long standing problem in the anti-backlash capability of the antenna drive controller has been resolved, significantly improving telescope tracking under windy conditions. This was fixed from the October/November session onwards. J.F.H. Quick 8 November 2007